1965183 - Consider to set microtask level to 0 when dispatching events

Status: RESOLVED FIXED

(Remote Protocol :: Agent, enhancement, P2)

Description

[Olli Pettay [:smaug][[e-mail]]]

I'm not sure if this works, but something like this might be needed for promise heavy tests like
https://searchfox.org/mozilla-central/rev/29184ec2b107c8b9dd8c9a594711c27545dfb2c7/testing/web-platform/tests/pointerevents/pointerevent_lostpointercapture_remove_setcapture_node.html

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

Attachment: Bug 1965183 - Consider to set microtask level to 0 when dispatching events, r=whimboo

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

The reason we need this is that because Marionette is implemented in JS, and window actors have their callbacks implemented as webidl callbacks. Those function are treated as the top level JS execution. And that means that if dispatching some dom event (from that js callback) has a side effect of dispatching other events too, microtask checkpoint will run only after all the JS execution has stopped, not between the DOM events, like it would normally happen if events were dispatched natively. And not having normal microtask checkpoint means that mutation observer callbacks and promise callbacks get called at wrong time.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/2d38949c16ad
Consider to set microtask level to 0 when dispatching events, r=masayuki,webdriver-reviewers,whimboo

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f5379b8600bb
Revert "Bug 1965183 - Consider to set microtask level to 0 when dispatching events, r=masayuki,webdriver-reviewers,whimboo" for causing wpt failures @select-events-2.tentative.html.

Comment 5

[agoloman]

Backed out for causing wpt failures @select-events-2.tentative.html.

• Backout link
• Push with failures
• Failure Log

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/851d81a8022d
Consider to set microtask level to 0 when dispatching events, r=masayuki,webdriver-reviewers,whimboo

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/92a90ab1cdae
Revert "Bug 1965183 - Consider to set microtask level to 0 when dispatching events, r=masayuki,webdriver-reviewers,whimboo" for causing wpt failures in select-events-2.tentative.html.

Comment 8

[Olli Pettay [:smaug][[e-mail]]]

No links to new failures?

Comment 9

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)(sick)]

I think that's this.

Comment 10

[Olli Pettay [:smaug][[e-mail]]]

Thanks!

(select popup handling is still a bit weird when it comes to microtasks. It doesn't use normal event handling)

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fed8d1373082
Consider to set microtask level to 0 when dispatching events, r=masayuki,webdriver-reviewers,whimboo

Comment 12

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/fed8d1373082